* [PATCH v2] gdb/jit: add function symbols to global block
@ 2026-01-06 18:15 Jan Vrany
2026-01-13 16:20 ` Tom Tromey
0 siblings, 1 reply; 6+ messages in thread
From: Jan Vrany @ 2026-01-06 18:15 UTC (permalink / raw)
To: gdb-patches; +Cc: Jan Vrany
This V2 updates the code to use std::vector rather than pending list
as commit "gdb/buildsym: replace struct pending with std::vector" removed
the latter.
Also note that this needs to be applied after
https://inbox.sourceware.org/gdb-patches/20251211161826.2365983-1-jan.vrany@labware.com/
Thanks,
Jan
-- >8 --
While playing with JIT reader I realized that it is not possible to set
a breakpoint on jitted function:
(gdb) b jit_function_stack_mangle
Function "jit_function_stack_mangle" not defined.
Make breakpoint pending on future shared library load? (y or [n])
The problem is that symbols for jitted functions (jit_function_stack_mangle
in the above example) are not added to jitted compunit's global block:
(gdb) maint print symtabs
...
Symtab for file at 0x55d6f8c186c0
Read from object file << JIT compiled code at 0x5555555592a0 >> (0x55d6f8cd4090)
Language: unknown
Line table:
line 1 at 0x7ffff7fbc000 (stmt)
line 0 at 0x7ffff7fbc001 (stmt)
Blockvector:
block #000, object at 0x55d6f8c188b0, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
block #001, object at 0x55d6f8c18910 under 0x55d6f8c188b0, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
block #002, object at 0x55d6f8c18730 under 0x55d6f8c18910, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc00a, function jit_function_stack_mangle
block #003, object at 0x55d6f8c187f0 under 0x55d6f8c18910, 0 symbols in 0x7ffff7fbc00a..0x7ffff7fbc011, function jit_function_add
This commit changes JIT reader to add jitted functions to the global
block:
...
Blockvector:
block #000, object at 0x55ed6665b180, 2 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
void jit_function_stack_mangle(); block object 0x55ed6665b000, 0x7ffff7fbc000..0x7ffff7fbc00a
void jit_function_add(); block object 0x55ed6665b0c0, 0x7ffff7fbc00a..0x7ffff7fbc011
block #001, object at 0x55ed6665b230 under 0x55ed6665b180, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
block #002, object at 0x55ed6665b000 under 0x55ed6665b230, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc00a, function jit_function_stack_mangle
block #003, object at 0x55ed6665b0c0 under 0x55ed6665b230, 0 symbols in 0x7ffff7fbc00a..0x7ffff7fbc011, function jit_function_add
---
gdb/jit.c | 17 +++++++++++++----
gdb/testsuite/gdb.base/jit-reader.exp | 10 ++++++++++
2 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/gdb/jit.c b/gdb/jit.c
index 489386393a1..214d984147e 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -43,6 +43,7 @@
#include "completer.h"
#include <forward_list>
#include "expanded-symbol.h"
+#include "buildsym.h"
static std::string jit_reader_dir;
@@ -564,6 +565,7 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
object for each. Simultaneously, keep setting the real_block
fields. */
int block_idx = FIRST_LOCAL_BLOCK;
+ std::vector<symbol *> global_symbols;
for (gdb_block &gdb_block_iter : stab->blocks)
{
struct block *new_block = new (&objfile->objfile_obstack) block;
@@ -585,6 +587,7 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
block_name->m_name = obstack_strdup (&objfile->objfile_obstack,
gdb_block_iter.name.get ());
+ global_symbols.push_back (block_name);
new_block->set_function (block_name);
@@ -606,12 +609,18 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
struct block *new_block;
if (i == GLOBAL_BLOCK)
- new_block = new (&objfile->objfile_obstack) global_block;
+ {
+ new_block = new (&objfile->objfile_obstack) global_block;
+ new_block->set_multidict (
+ mdict_create_linear (&objfile->objfile_obstack, global_symbols));
+ }
else
- new_block = new (&objfile->objfile_obstack) block;
+ {
+ new_block = new (&objfile->objfile_obstack) block;
+ new_block->set_multidict (
+ mdict_create_linear (&objfile->objfile_obstack, {}));
+ }
- new_block->set_multidict
- (mdict_create_linear (&objfile->objfile_obstack, {}));
new_block->set_superblock (block_iter);
block_iter = new_block;
diff --git a/gdb/testsuite/gdb.base/jit-reader.exp b/gdb/testsuite/gdb.base/jit-reader.exp
index 549859627f1..8b3f50d15b7 100644
--- a/gdb/testsuite/gdb.base/jit-reader.exp
+++ b/gdb/testsuite/gdb.base/jit-reader.exp
@@ -244,6 +244,16 @@ proc jit_reader_test {} {
"<gdb.Objfile filename=<< JIT compiled code at $hex >>>" \
"python gdb.Progspace.objfile_for_address"
}
+
+ # Check that jitted symbol completion works
+ gdb_test "complete break jit_func" \
+ [multi_line "break jit_function_add" \
+ "break jit_function_stack_mangle" ] \
+
+ # Check that breakpoint can be set on jitted function
+ gdb_test "break jit_function_add" \
+ "Breakpoint 1 at 0x\[0-9a-f\]+"
+ gdb_test_no_output "del 1"
}
}
--
2.51.0
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] gdb/jit: add function symbols to global block
2026-01-06 18:15 [PATCH v2] gdb/jit: add function symbols to global block Jan Vrany
@ 2026-01-13 16:20 ` Tom Tromey
2026-01-13 21:42 ` Jan Vraný
2026-01-14 10:44 ` [PATCH v3] " Jan Vrany
0 siblings, 2 replies; 6+ messages in thread
From: Tom Tromey @ 2026-01-13 16:20 UTC (permalink / raw)
To: Jan Vrany; +Cc: gdb-patches
>>>>> "Jan" == Jan Vrany <jan.vrany@labware.com> writes:
Jan> + {
Jan> + new_block = new (&objfile->objfile_obstack) global_block;
Jan> + new_block->set_multidict (
Jan> + mdict_create_linear (&objfile->objfile_obstack, global_symbols));
Jan> + }
Jan> else
Jan> - new_block = new (&objfile->objfile_obstack) block;
Jan> + {
Jan> + new_block = new (&objfile->objfile_obstack) block;
Jan> + new_block->set_multidict (
Jan> + mdict_create_linear (&objfile->objfile_obstack, {}));
Jan> + }
Does anything ever get added to the static block?
If not then making a dictionary doesn't seem necessary?
Also the formatting is wonky here, that "(" should not be at the end of
the line. (Two instances of this.)
Kind of weird that this code doesn't use buildsym, but OTOH buildsym is
horrible.
Tom
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] gdb/jit: add function symbols to global block
2026-01-13 16:20 ` Tom Tromey
@ 2026-01-13 21:42 ` Jan Vraný
2026-01-13 22:47 ` Tom Tromey
2026-01-14 10:44 ` [PATCH v3] " Jan Vrany
1 sibling, 1 reply; 6+ messages in thread
From: Jan Vraný @ 2026-01-13 21:42 UTC (permalink / raw)
To: tom; +Cc: gdb-patches
On Tue, 2026-01-13 at 09:20 -0700, Tom Tromey wrote:
> > > > > > "Jan" == Jan Vrany <jan.vrany@labware.com> writes:
>
> Jan> + {
> Jan> + new_block = new (&objfile->objfile_obstack) global_block;
> Jan> + new_block->set_multidict (
> Jan> + mdict_create_linear (&objfile->objfile_obstack, global_symbols));
> Jan> + }
> Jan> else
> Jan> - new_block = new (&objfile->objfile_obstack) block;
> Jan> + {
> Jan> + new_block = new (&objfile->objfile_obstack) block;
> Jan> + new_block->set_multidict (
> Jan> + mdict_create_linear (&objfile->objfile_obstack, {}));
> Jan> + }
>
> Does anything ever get added to the static block?
No (at the moment).
> If not then making a dictionary doesn't seem necessary?
As the code stands now, I think it has to - the rest of code expects it is
always there. For example, blockvector::~blockvector() just unconditionally
frees the dictionary. Or blpy_repr() that calls mdict_size().
>
> Also the formatting is wonky here, that "(" should not be at the end of
> the line. (Two instances of this.)
Sorry, will fix that.
Jan
>
> Kind of weird that this code doesn't use buildsym, but OTOH buildsym is
> horrible.
>
> Tom
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] gdb/jit: add function symbols to global block
2026-01-13 21:42 ` Jan Vraný
@ 2026-01-13 22:47 ` Tom Tromey
0 siblings, 0 replies; 6+ messages in thread
From: Tom Tromey @ 2026-01-13 22:47 UTC (permalink / raw)
To: Jan Vraný; +Cc: tom, gdb-patches
>>>>> "Jan" == Jan Vraný <Jan.Vrany@labware.com> writes:
>> If not then making a dictionary doesn't seem necessary?
Jan> As the code stands now, I think it has to - the rest of code expects it is
Jan> always there. For example, blockvector::~blockvector() just unconditionally
Jan> frees the dictionary. Or blpy_repr() that calls mdict_size().
Gotcha, thanks for looking.
Maybe at someday we should let mdict_free take a null pointer and
then we could omit empty dictionaries for some blocks.
Tom
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v3] gdb/jit: add function symbols to global block
2026-01-13 16:20 ` Tom Tromey
2026-01-13 21:42 ` Jan Vraný
@ 2026-01-14 10:44 ` Jan Vrany
2026-01-14 13:42 ` Tom Tromey
1 sibling, 1 reply; 6+ messages in thread
From: Jan Vrany @ 2026-01-14 10:44 UTC (permalink / raw)
To: tom, gdb-patches; +Cc: jan.vrany
This v3 just fixes formatting (no opening parenthesis at the end of the line).
-- >8 --
While playing with JIT reader I realized that it is not possible to set
a breakpoint on jitted function:
(gdb) b jit_function_stack_mangle
Function "jit_function_stack_mangle" not defined.
Make breakpoint pending on future shared library load? (y or [n])
The problem is that symbols for jitted functions (jit_function_stack_mangle
in the above example) are not added to jitted compunit's global block:
(gdb) maint print symtabs
...
Symtab for file at 0x55d6f8c186c0
Read from object file << JIT compiled code at 0x5555555592a0 >> (0x55d6f8cd4090)
Language: unknown
Line table:
line 1 at 0x7ffff7fbc000 (stmt)
line 0 at 0x7ffff7fbc001 (stmt)
Blockvector:
block #000, object at 0x55d6f8c188b0, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
block #001, object at 0x55d6f8c18910 under 0x55d6f8c188b0, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
block #002, object at 0x55d6f8c18730 under 0x55d6f8c18910, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc00a, function jit_function_stack_mangle
block #003, object at 0x55d6f8c187f0 under 0x55d6f8c18910, 0 symbols in 0x7ffff7fbc00a..0x7ffff7fbc011, function jit_function_add
This commit changes JIT reader to add jitted functions to the global
block:
...
Blockvector:
block #000, object at 0x55ed6665b180, 2 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
void jit_function_stack_mangle(); block object 0x55ed6665b000, 0x7ffff7fbc000..0x7ffff7fbc00a
void jit_function_add(); block object 0x55ed6665b0c0, 0x7ffff7fbc00a..0x7ffff7fbc011
block #001, object at 0x55ed6665b230 under 0x55ed6665b180, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc011
block #002, object at 0x55ed6665b000 under 0x55ed6665b230, 0 symbols in 0x7ffff7fbc000..0x7ffff7fbc00a, function jit_function_stack_mangle
block #003, object at 0x55ed6665b0c0 under 0x55ed6665b230, 0 symbols in 0x7ffff7fbc00a..0x7ffff7fbc011, function jit_function_add
---
gdb/jit.c | 16 ++++++++++++----
gdb/testsuite/gdb.base/jit-reader.exp | 10 ++++++++++
2 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/gdb/jit.c b/gdb/jit.c
index 489386393a1..4add2fa4861 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -564,6 +564,7 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
object for each. Simultaneously, keep setting the real_block
fields. */
int block_idx = FIRST_LOCAL_BLOCK;
+ std::vector<symbol *> global_symbols;
for (gdb_block &gdb_block_iter : stab->blocks)
{
struct block *new_block = new (&objfile->objfile_obstack) block;
@@ -585,6 +586,7 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
block_name->m_name = obstack_strdup (&objfile->objfile_obstack,
gdb_block_iter.name.get ());
+ global_symbols.push_back (block_name);
new_block->set_function (block_name);
@@ -606,12 +608,18 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
struct block *new_block;
if (i == GLOBAL_BLOCK)
- new_block = new (&objfile->objfile_obstack) global_block;
+ {
+ new_block = new (&objfile->objfile_obstack) global_block;
+ new_block->set_multidict
+ (mdict_create_linear (&objfile->objfile_obstack, global_symbols));
+ }
else
- new_block = new (&objfile->objfile_obstack) block;
+ {
+ new_block = new (&objfile->objfile_obstack) block;
+ new_block->set_multidict
+ (mdict_create_linear (&objfile->objfile_obstack, {}));
+ }
- new_block->set_multidict
- (mdict_create_linear (&objfile->objfile_obstack, {}));
new_block->set_superblock (block_iter);
block_iter = new_block;
diff --git a/gdb/testsuite/gdb.base/jit-reader.exp b/gdb/testsuite/gdb.base/jit-reader.exp
index 549859627f1..8b3f50d15b7 100644
--- a/gdb/testsuite/gdb.base/jit-reader.exp
+++ b/gdb/testsuite/gdb.base/jit-reader.exp
@@ -244,6 +244,16 @@ proc jit_reader_test {} {
"<gdb.Objfile filename=<< JIT compiled code at $hex >>>" \
"python gdb.Progspace.objfile_for_address"
}
+
+ # Check that jitted symbol completion works
+ gdb_test "complete break jit_func" \
+ [multi_line "break jit_function_add" \
+ "break jit_function_stack_mangle" ] \
+
+ # Check that breakpoint can be set on jitted function
+ gdb_test "break jit_function_add" \
+ "Breakpoint 1 at 0x\[0-9a-f\]+"
+ gdb_test_no_output "del 1"
}
}
--
2.51.0
^ permalink raw reply [flat|nested] 6+ messages in thread
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2026-01-06 18:15 [PATCH v2] gdb/jit: add function symbols to global block Jan Vrany
2026-01-13 16:20 ` Tom Tromey
2026-01-13 21:42 ` Jan Vraný
2026-01-13 22:47 ` Tom Tromey
2026-01-14 10:44 ` [PATCH v3] " Jan Vrany
2026-01-14 13:42 ` Tom Tromey
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